Physical Layer Security via Frequency Domain Signal Segmentation
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Solution Overview
Problem
Existing wireless communication systems face challenges in maintaining physical layer security without additional channel information or security keys, particularly when the number of antennas of an eavesdropper exceeds those of the transmitter, and in bi-directional communication environments.
Innovation Solution
A method for distinguishing subcarriers used for data and jamming signals in a wireless communication system based on amplitude or phase thresholds, allowing secure communication without pre-shared security keys, using a single or multiple antennas, by determining specific frequency regions for data and jamming signal transmission through a preamble sequence and channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a security key shared by transmitter and receiver is used to prevent eavesdropping, then security can be maintained under normal conditions, but security cannot be maintained when the security key is leaked
Solution Approach 1:
The patent segments the frequency spectrum into multiple subcarriers and transmits data and jamming signals on different subcarriers. This segmentation allows the system to maintain security through physical layer techniques rather than relying solely on higher-layer security keys, thereby addressing the vulnerability when keys are leaked while reducing key management complexity
Solution Approach 2:
The patent converts the potentially harmful jamming signal into a beneficial security mechanism. By transmitting jamming signals on specific subcarriers, the system actively prevents eavesdropping on those subcarriers, transforming what could be interference into a security feature that protects against key leakage vulnerabilities
2Reliability
If artificial noise or jamming signal is applied to maintain security when channel information is unknown, then security can be maintained, but the transmitter should use a plurality of antennas
Solution Approach 1:
The patent moves the security mechanism from the spatial dimension (requiring multiple antennas) to the frequency dimension (using multiple subcarriers). By applying jamming signals on specific frequency subcarriers rather than requiring multiple spatial antennas, the system maintains security while reducing hardware complexity and antenna requirements
Solution Approach 2:
The patent changes the operational parameter from spatial configuration (number of antennas) to frequency configuration (subcarrier allocation). This parameter change allows the system to achieve the same security effect using frequency domain resources instead of spatial resources, thereby reducing the number of antennas needed
3Reliability
If physical layer security scheme is used, then security can be maintained with single antenna, but security cannot be maintained when the number of antennas of the eavesdropper exceeds the number of antennas of the transmitter
Solution Approach 1:
The patent segments the transmission into multiple subcarriers, with some subcarriers carrying data and others carrying jamming signals. This segmentation creates frequency-domain isolation that prevents an eavesdropper with more antennas from easily combining signals to break security, as the jamming signals on dedicated subcarriers protect the data subcarriers regardless of the eavesdropper's antenna count
Solution Approach 2:
The patent introduces jamming signals as an intermediary element that mediates between the transmitter and eavesdropper. These jamming signals on specific subcarriers act as a protective barrier that prevents the eavesdropper from successfully decoding data, even when the eavesdropper has superior antenna resources compared to the transmitter
4Reliability
If jamming signal is transmitted on null space of channel between transmitter and receiver, then security can be maintained, but additional channel information related to eavesdropper is required
Solution Approach 1:
The patent enables the system to determine jamming subcarriers autonomously based on channel estimation performed by the receiver and fed back to the transmitter. This self-service mechanism eliminates the need for additional channel information about the eavesdropper, as the system uses only the legitimate channel between transmitter and receiver to make security decisions
Data Source
AI summary
An operation method of a terminal in a wireless communication system includes receiving a preamble sequence from a base station; estimating a UL channel between the terminal and the base station based on the preamble sequence; determining a first frequency region for transmitting a data signal and a second frequency region for transmitting a jamming signal in an entire frequency region of the UL channel based on a result of estimating the UL channel; and transmitting to the base station a UL control signal including identification information for identifying the first frequency region and the second frequency region.